Method of and apparatus for finishing bulbs



W. R. BURROWS.

METHOD OF AND APPARATUS FOR FINISHING BULBS.

APPLICATION FILED MAR. 3l. 1919.

Patented Jan. 24, 1922` w F a .f m Q. .-.TAI/,4 d 9 7 d. n 2 4. r2.5 m m Inventor: William R. Burrows,

His 'Htto1`r e\.

W. R. BURROWS.

METHOD 0F AND APPARATUS FOR FINISHING BULBS.

APPLICATION FILED MAR. 31. I9I9.

1,404,268. Patented Jan. 24, 1922.

4 SHhtS-SHEET 2.

Inventor; William 'R Burrows,

bg MQW/@M His YlttoVneg.

W. R. BURROWS.

METHOD 0F AND APPARAus FOR FlNlsHlNG BULBS.

| 1919- Patlted Jan. 24, 1922.

APPLICATION HLED MAR, 31

4 suus-SHEET 3.

Fig. 9.

His ttorneg ITUVeTDtOT; WH am R. Burr-OWS, by

Fig. l2.

W. R. BURROWS.

METHOD 0F AND APPARATUS FOR FINISHING BULBS.

APPLICATION FILED III/IR. 31. I9I9.

1,404,268. Patented Jan. 24, 1922.

4 SHttIS-S-HEET 4.

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IIlII 'iiiiiliiiiiiflilii Inventor: Wil icm R. B LLTTOWS,

His 'lttovheg lso , l METHOD 0I AND APPARATUS FOR FINISHING BULBS.

Speclcation of Letters Patent.

PATENr orifice.

AssIGNoa' To GENERAL ELECTRIC NEW YORK.

Application led Karch- 31, 1.919. Serial No. 286,593.

- To atl whom it may concern:

Be it known that I, WILLIAM R. BURRows, a citizen' of the United States, residing at Newark, county of Essex, State of New ersey, have invented certain new and useful Improvements in Methods of and Ap aratus for Finishing Bulbs, of which the fo lowing is a specification. n

Incandescent lamp bulbs are usually blown with long necks having on the end a thick ring or mass of glass which adheres to the blow pipe during the blowing of the bulb,

and which must be removed before the bu b can be used. To facilitate removal of thls waste portion of the neck, the presentpractice is to form a convex swell or bead 1n the neck a short Ydistance above the thick end. The bulbs are'sent to the lamp factory just as they come from the mold, and at the lamp factory the waste end of the neck is cracked oflt' by heating a thin line or zone on the crest of the swell or bead and then touching the heated bead to a cold iron or a moistened stone, thereby starting a crack which runs around the neck along the heated zone on the bead. The bead adds tothe difficulty of blowing the bulb, as the body of the bulb is' blown from very hot glass and requires an air pressure of only a few ounces per square inch. The thin walls of the neck cool somewhat during the blowing, so that when the bead or swell is finally formed the glass is comparatively cool and a pressure of three or four pounds per square inch is required. The shrinkage or breakage of bulbs in the bulb factory is great even when the bulbs are carefully annealed, because the thick mass of glass Ion the end of the neck of the freshly blown bulb sets up severe strains in the walls ofthe bulb during cooling. More breakage occurs in the lamp factory when the bulbs with strains in them are heated up in the cracking offoperation and also because a crack which starts in the bead will often ex- ,tend up the neck toward the body of the -bulb instead of following the bead.

The object of my invention is to reduce the breakage of bulbs and similar articles of glassware. Another object is to produce bulbs more free from strain than the ordinary bulbs, and with necks of the proper length and a well finished edge. Still another object is to provide an improved method of and apparatus for removing the fi waste' glass from the neck'of bulbs and simtion in the lamp factory. A still iPatented Jan. 24, 1922. l

ilar articles in the bulb factory.` further object is to eliminate the cracking off o rafurther ob- ]ect 1s to cheapen and 1mprove the manufacture of incandescent lamp bulbs and similar articles of glassware.

(A freshly blownbulb as it comesfrom the` mold is so hot that it is free from permanent strains. By my method all of the glass working operations for removing the waste glass and preparing the bulb for use in the lamp factoryare performed on a freshly blown bulb before it cools to the critical temperature of about a0()o C. where permanent strains develop in it. No bead or swell to fac1l1tate crac ing off is necessary, as I remove the waste portion by heating a narrow zone on the neck of the freshly blown and lot bulb until the waste portion of the neck can be pulled ofl".v In many cases I then finish the hot Ledge of the neck by reaming 1t out to the proper bore and smoothing u the edge while the glass is still plastic. The

finished bulb thus produced is more free from strains than the bulbs heretofore used in the lamp factory, because it was blown with much less air pressure thanrequired when a bead is formed and the use of this lower air pressure leaves less strains in the glass; because no thick mass of glass is attached to the end of cause all of the glass the bulb were performed while it was still above the critical temperature and so hot as to be free from strains.

My invention may be carried out in various ways, but for the best results I provide an automatic or semi-automatic apparatus which is well adapted for the practice of my method of bulb making, and is also very useful in removing waste glass from any necked vessel. This apparatus automatically removes Fthe waste end from the bulb, and then flares or reams out the neck and finishes the edge. Y In practicing my method with this apparatus the freshly blown bulb without a bead is stripped from the blow pipe or discharged from the automatic bulb blowing machine while still so hot as to be free from strain, immediately` suspended neck down in a travelling head, and carried the neck; and also be- Working operations on to the cutting off position, where cutting 0H .i

fires heat a narrow zone on the neck and ngers seize the neck below the heated zone and exert enough pull by gravity to pull off the waste -Ipart below the heated zone. The bulb, still Avery hot, is carried to another position where the neck, still plasticls liared or reamed out, if necessary, until the bore is of the proper size and the plastic edge is- .smooth The glass working operatwns on be understood in connection with the accompanying drawings, in which I have shown merelyfor purposes of illustration one of the various lforms of apparatus suitable lfor ythe practice of my invention, and in which Fig. 1 is a view looking down upon the apparatus;\Fig.'2 is a vertical section along the (vertical vaxis of the bulb carrying turntable; Fig. 3 is a view of the turn-table locking mechanism with certain parts broken away; Fig. y4 a side view of the bulb stripper and bulbmagazine at the loading position of the apparatus, with a bulb readyto be' stripped from the blow-pipe; Fig. 5a view of the bulb stripper of Fig. 4 just after the bulb has been stripped from the blow-pipe;

Fig. 6 an end view of the bulb magazine and feed chute at the loading position; Fig. 7 a side view of the feed chute and associated parts; Fig. 8 a view of the bulb buffer shown in Fig. 7; Fig. 9' a view looking down-upon the cutting of burners andpull off ngers for removing the waste portion of the bulb; Fig.f10 a side view of the parts shown in Fig.

v '9 with/the pull ofi' fingers at the beginning j of the cutting off operation; Fig. 11 a view e similar to Fig. 10 but'with the ull off fingers at the end'of the cuttingo operation; Fig. 12 a side view of parts ofthe flaring or reaming mechanism at the beginning of the flaring operation; Fig. 13 a view of the ilaring mechanism at the end of `the flaring operation; Fig. 14 atop View of the arm of drawings a horizontally movable bulb carrying mechanism is mounted on a base 1 A drive shaft 2 operates various parts of the kapparatus 'by means of vcams on the shaft,

and also drives the bulb carrying mechanism through intermittent gears 3 and 4 between the drive shaft and a stub shaft-5. The intermittent motionof the Astub shaft 5 is transmitted through bevel gears and a' ion 6 -to the bulb carrying mechanism w ich -automatically places each bulb in-a number of "different positions where the different glass working operations arb performed.

turnftable 7 with its hub geared to the intermittently rotating pinion 6. In the The bulb carrying mechanism comprises a mechanism shown the turn-tableis'provided with six rotatable bulb holders or heads 8, each in the form of a tubular pinion mounted on the turn-table in a ball bearing and having a central opening of such a size that a bulb Will be held in the head with the neck projecting lbelow the head. All six heads arev ycontinuously rotated through a head driving gear 9 in mesh with all of the heads and driven through bevel gears 10 and a stub shaft 11 from the drive shar`t'2.

To hold the turn-table 7 steady in the various positions, I provide a latchingA mechanism, best shown in Fig. 3, and comprisinga notched wheel 12 on the hub of the .turn-table and a cooperating detent 13 onthe base. \A cam on the drive shaft 2 holdsthe detent out of the notch while the' waste glass from bulbs which have been al-v lowed. to cool just as they come from the mold, and if the bulbs are cold they may be loaded by hand. To facilitate the practice of my method and the loading of the bulbs roo into the .cutting olf apparatus while they are still hot, I provide an automatic loader The apparatus can be used with any kind of bulb blowing machine, suchv as the semi-automatic machine which delivers to the operator a removable blow pipe with the bulb attached to it, or the full automatic machine which delivers the bulb detached from the blow pipe. tus as used with a semi-automatic bulb blowing machine, and in'this particular arrangiement a freshly blown bulb 14 with the heayy ring or mass of glass 15 on the end of the neck is detached -from the removable blow pipe 16 of the semi-automatic machine by. a bulb stripper 17'.l in the form of a metal block with a notch just large enough for the blow pipe 16. The mass or ring of glass 15 which adheres to the blow pipev and forms the end of the neck of the freshly blown I have shown the apparaf bulb is too large to pass vthrough the notch through the notch of the stripper, as indi-l I ,cated in Fig. 5, the mass of glass 15 catches "cutting off the intensely bulb.'l

on the stripper, and the freshl blown hot bulb is pulled off the blow pipe liy the stripper and left lying in a bulb ma azine 18. If the bulb is defective it can be roken oil' the end of the blow pipe and left inla waste chute'19. y

The hot bulb 14 in the magazine 18 is yautomatically loaded into a head 8 before it cools down ap reciabl and before' strains develop in it. 'llhe ho't lymlb is removed from the magazine 18 in 'any suitable way, for example by means of a pivoted fioor 20,

which is lowered at l`the proper time by a cam 21 on the drive shaft 2, whereupon the hot bulb "rolls into a tiltin feed chute 22 in the position shown'in ful lines in Fig. 7.. The feed chute is mounted on a pivot 23 at one end, and is lifted by a cam 24 on the Vdrive shaft 2 into the position shown in dotted lines to cause the bulb to slide endwise out of the chute and into the head V8, where it is held with the neck down.

, In some cases I provide the feed chute 22 with a pivoted gate 25 which prevents the bulb sliding out of the chute. The gate 1s automatically openedl at the end 0f the tilting movement of the feed chute by means of a stationary lifter 26 which is caught by the projecting end of the pivot gate as the feed chute reaches the position shown in dotted,

lines.

To place/the bulb in the head 8 with minimum shock I provide a vertically movable buffer block 27 actuated by the cam 28 so that it will be close to the bottom of the head 8, as shown in Fig. 8, when the bulb slides out of the chute 22, and will` then slowly drop and gently lower the bulb into place in the head.

In the automatic loading device just described the freshly blown hot bulb is delivered to the feed chute, and then placedv neck down in the rotating head 8 so quickly that it is placed inthe head 8 at position A,

and made ready for subsequentglass working operations while it is still far above the critical temperature 'at which strains develop.

As soon as the bulb is A the turn-table 7 is automatically shifted one step to carry the hot bulb to the next position B, where the bulb is-held for a short .time until the air inside of it cools down slightly, although the bulb remains above the critical temperature at which strains develop. Unless this is done a thin film of glass sometimes forms across theneck of the bulb in 'subsequent operations, and is sucked up into the bulb heated air in the body ofthe From position'B the bulb is carried to the positlon C where a narrow zone on the neck of the bulb some distance above the end is heated by burners 29, which give vand pull ofi' thepwaste loaded at position by the cooling ofa flat flame, until the glass in the narrow heated zone becomes so soft that the waste glass can easily be pulled off. At( the same time a burner 30 directs a soft brush like flame on the to of the bulb to anneal it and keep it'hot.'

haps collapse, and be closed up by a film of glass@ In accordance with my invention I provide means for pulling olf and removing Vf the glass ismelted by the burners 29,.'the neck will shrink and perthe waste portion of the' neck before the ngers` constructed' and shaped to grasp the end of the neck below the heated zone portion. In the particular arrangement which I prefer two horizontal blades of a pair of scissors are held. together by a spring32. When a bulb arrives at the cutting off position C the pull ofi?` fingers automatically separate, rise with the neck of thebulb between them` then approach each other, and grip the neck just below the narrow heated zone, and then areleft free to exert by their weight a strain tending to pull the waste end of the neck away from the remainder;

To permit the pull off fingers to rise and grasp the neck of the bulb and then exert a downward pull upon the end of the bulb, I pivot them upon a rocking block 33 which is rocked about a horizontal axis by aA cam fdllower 34 and a plate cam 35 on the drive shaft 2. The fingers are opened and closed by a finger spreading cam, such as a vertical spreading cam 36, oval in cross section, and of such a length that as the pull ofi' fingers rise and fall they slide lengthwise of the cambut do not get out of contact with it. The spreading cam is rotated by a plate cam 37 on the cam shaft 2, and spreads the fingers farenough apart" so that they can easily pass over the neck of the the cam is crosswise.

As the bulb comes into the cutting off position C, the pull off fingers are down out of the way, as indicated in Fig. 9. The finger spreader cam 36 turns crosswise and spreads the fingers, and then the rocking block 33 raises the fingers into the position shown in Fig. 10, whereupon the spreader cam 36 turns backl and permits the pull off fingers to be drawn toward each other by the spring and to grip the neck of the bulb just below the zone heated by the burners 29. Where the finger raising cam 35 on the shaft 2 runs out from under the end of the cam follower 34 the weight of the fingers and associated parts tends' to pull off the waste end of the neck as soon as the glass has been softened by the ames of the burners 29-and before pull off fingers 31 pivoted like the bulb when the neck of the bulb is hot enough to coll so that if the separation of the waste portion from the remainder of the bulb is started, it will surely be completed.

The bulb with the waste portion cut-od is then carried to the flaring position D where the edge of the neck, still plastic from the heat of the burners 29, is' flared or reamed out so as to insure that the neck of the bulb will be of the proper bore and that the edge will be smooth and rounded. *For this operation I prefer to use a flaring or reaming device, such as is shown in Fig. 12 and comprising a reamer 39 in the form of a pencil or wiper, preferably of carbon, pivoted at the upper end, and so mounted that it can be thrust into the neck of the bulb and then swung out laterally, so as to flare and smooth the edge of the neck. This movement of the reamer can be accomplished by various mechanisms, but in the preferred constructionthe reamer is pivoted at the'upper end to a vertical rod 40 mounted in a verticall movable sleeve 41 and movable lengthwise of the sleeve, though normally held inthe `position shown in Fig. 12 by a spring 42 inside the sleeve. The lower end of the reamer39 is swung out by means ofa link 43 pivoted to thelower end of the reamer and to the sleeve 41. When the reamer rises into the neck-of the bulb the parts are in the position shown in Flg. 12. The upward .movement of the rod 40 is .stopped at a definite point by a projection reaming position shown in Fig.' 13. As a result of thisaction the neck of the bulb is flared out slightlyy and the edge is smoothed and rolled back into a well finished edge.

The neck may not flare out easily under all conditions and in some cases I provide an abutment or steadying means, such as a roller 46, for supporting the I leck duringthe flaring operation and for reslsting the sidewis'e thrust of the reamer 39. I may also.

facilitate the flaring and smoothing of the was above the critical temperature at which v @trains develop in a. .The finished bulb is now carried to theannealing position E,. where 1t is allowed to cool down, andv then to the final or discharge position F' ,wheriejff' it is removedfrom the apparatus.

A convenient form of automatic discharge or transfer mechanism for removing the finished bulb 1s illustrated in Figs. 14 and 15,

in which a transfer arm 48 is provided at one end with gripping fingers 49, preferably flexible, and shaped'to grasp the large end of a bulb. I prefer to provide these fingers Ywith non-metallic tips, of wood or asbestos. The fingers are opened and closed by means.

o f a rocker 50 which carries some of the fingers', while the others are rigidly attached to the arm 48. The transfer arm is mounted on a vertical rod 51 which is automatically raised and lowered by a cam 52, and also turned back and forth` by a cam 53 on the drive shaft 2. As a head 8 arrives at the discharge position F, the rod 51 is lowered to bring grippin fingers 49' into position to get hold of the ibulb, then raised vertically to lift the bulb out of the head,then swung horizontally, and then lowered into release position to discharge the finished bulb. To cause the fingers 49 to let loose of the bulb as the transferarm 48 is lowered into the release position, I mount a stop` 54 in the path of an arm on the rocker 50, to rock it andopen the gripping fingers 49 until they drop the bulb. The transfer arm then rises and swings back, to the origi'n'al position, ready to pick up the next bulb. To' assist the discharge mechanism' in getting hold of the bulb I provide a vertically movable bulb ejector 55 actuated from the drive shaft 2 and so timed that as soon as the head8',

lwith the finished bulbin it, stops in the vdischarge position F', the bulb" ejector 55 begins to rise and pushes the bulb up out of the head. At the `same time the gripping fln-v gers 49 have been lowered into place immeditely above the head, so thatthe bulb lifted out of thehead 8 by the ejector 55, is .pushed up into the resilient gripping fin ers which spring open slightly and permi the bulge of the bulb to passl up beyond the ti s of the fingers, thereby permitting the. n ers to grasp the bulb and lift it out of the ead as the transfer arm is raised. i

What I claim as new and desire tosecure by Letters Patent of the United States, is

1. The method of finishing a blown glass bulb while it is still so hot from the mold, as to be free from strains which consists in softening the neck of the hot bulb along a zone so narrow that the bore of the neck is not, substantially reduced, and detaching the waste end of the neck from the bulb at said zone .before the glass becomes' cool enough to develop strains.

2. The method of finishing a blown glass ros bulb which consists in heating the neck of the bulb while still so hot from the molt as to be free from strainsto substantially the melting point along a zone so narrow that the waste end is detached without substantial reduction in the diameter in the bore of the neck, and enlargin the hot end of the neck until it exceeds tie minimum bore, of the neck. v

3. The method of finishing a freshly blown glass bulb which consists in melting off the surplus neck along a narrow zone while the glass of the bulb `is still so hot from the mold asto be free from strains and reaming out the hot end of the neck until its bore is at least equal tol that of the remainder of the neck.

4. The method of finishing a freshly blown glass bulb which consists in melting off the surplus neck along a narrow zone while the glass of the bulb is still so hot from the mold as to be free from strains and lire finishing the edge of the neck before the glass becomes cool enough. to develop strains.

5. The meth of nishingafreshl blown glass bulb while still so hot from t e mold as to be free from strains which consists in fusing the neck along a zone so narrow that the waste 'end can be detached at said zone without substantial contraction of the neck and flaring the hot ed e of the neck to form a funnel larger than t e bore of the neck. 6. The method of finishing a blown glass bulb which consists in heatln the neck of the bulb while it is still so hot rom the mold as to be free from strains and thereby softening it along a zone so narrow that the neck does not collapse, and exerting lengthwise of the neck a pull sufficient to separate the waste end from the hot bulb at said zone before the strains.

7. The method of finishing a blownglass bulb which consists in suspending the bulb with the neck down while it is still so hot from the mold as to be free from strains, softening the neck of thehot bulb along a zone so narrow that the neck does not collapse, and exerting by gravity a pull suffcient to detach `t e waste end of the bulb at said zone.

and a heater for softening a zone on the neck of a bulb in said holden-of loading glass cools enough to develop.

mechanism for depositing a bulb in said holder, detaching mechanism for pullin olf the waste portion of the neck, smoot ling mechanism for the edge of the neck, discharge mechanism for removing the bulb from the holder, and common actuating means for intermittently movin said holder into register with said mechanisms in succession and for 'actuating said mechanism while in register with the holder.

10. In a machine of the character described, the combination with a tubular bulbholder, of loading mechanism comprisin a stripper for removing a freshly blown bu b from the blow Ipipe a movable feed chute for receiving the bulb and placing it neck down in said ho der, and common drlving means for moving said holder and actuating said chute.

. 11. In a machine of the character described,

the combination with a bulb holder, and a stripper for removing a bulb from the blow pipe, of loading `mechanism comprising a magazine adjacent said stripper tol receive the bulb, a feed chute adjacent said magazine for deliverin a bulb to said holder, and means for trans erring a bulb from said magazine to said chute.

12. In a machine of the character described, the combination with a tubular bulb holder, of loading mechanism comprising a stripper fuor removing a freshly blown bulb from the blow pipe, a tiltable feed chute mounted to receive the bulb and to slide it endwise into said holder when said chute is tilted, a vertically movable buil'er for the neck of the bulb immediately below said holder and in position when raised to keep the bulb out of the holder, and Adriving means for tiltin chute and subsequently lowering said uffer to lower thebulb gent y into the-holder.

13. In a machine of the character described, the combination with a vertical tubular bulb holder mounted to move horizontall of a vertically movable bulb buffer below t e path of said holder, and common actuating means for moving said holder into alignment with said buffer and for raising and lowering said buffer while in alignment.

14. In a machine of the character described, the combination with'a tubular bulb holder, of a tilting feed chute mounted to deliver a bulb neck down into said holder, a gate across the lower end of said chute, 'and means for automatically opening said gate as said chute moves into delivery position.

15. 'In a machine ofthe character described, the combination with a tubular bulb holder, of a tilting feed chute mounted to deliver a bulb neck down into said holder, a gate pivoted on said chute to normally close -its lower end, and a stop mounted to engage and open said gate as said chute tilts into deliverv position.

16, In a machine of the character, described, the combination with a-movable bulb said i lholder for holding a bulb in Vvertical posi- Vtion and burners for heating a narrow zone on the neck of the bulb in said holder, of pulling off means mounted adjacent the path' of the end of the neck of said bulb for grasping the waste end of. the neck and pulling lengthwise of the neck to sever the neck at said zone, and, actuating mechanism for bringing said bulb holder into operative relation to said pulling ofil meansand for automatically actuating said pulling ofi means to pull ofi' the waste end of the neck.

17. In a machine of the character described, the combination with a travelling bulb holder for holding a bulb in vertical position, and burners for heating a narrow zone on the neck of the bulb, of pull off fingers mounted adjacent said burners and movable in a direction to exert a pull longitudinally of the neck when applied to the neck, and common actuating means for said vbulb holder and said fingers for moving said holder and automatically applying said fingers to the waste end lof the neck.

18.' In a machine of the character described, the combination witha bulb holder for holding a bulb in vertical position, and burners for heating a narrow zone on the neck of the bulb, of cooperating fingers relatively movable horizontally to open and close and bodily movable vertically, said fingers being weighted to exert by gravity a pull on the neck, opening means for separating said fingers, lifting means for moving said fingers vertically into position to grasp the waste portion of the neck, and, actuating mechanism for said opening means and said lifting means for automatically opening said fingers, moving them while open into position to grasp the waste portion of the neck, andv then closing them on the neck.

19. In a machine ofthe character described, the combination'with a bulb holder for holding a bulb in vertical position, and burners for heating a narrow zone on the neck of' the bulb, of a vertically movable member constructed to engage the waste end of the neck, and actuating mechanism for automatically lifting said member and attaching it tothe waste end of the neck and then leaving it free .t0 descend by gravity.

20. In a machine of the character'described, the combination with a bulb holder for holding a bulb in verticalposition, and burners for heating a narrow zone on the neck of the bulb,of va block tiltable about a horizontal axis, a pair of fingers pivoted on said block to movehorizontally, a vertical cam between said fingers and rotatable about a vertical axis to open and close them, tilting means for positively tilting said block to raise the fingers and comprising a lost motion connection to permit said block to remain tilted with said fingers raised, and common driving means for turning said vertical cam to open said fingers, actuating said tilting means to raise the opened fingers, turning said vertical cam to close said fingers, and actuating said tilting means to vleave said block free to tilt and lower said fingers by gravity.

21. In a machine of the character described, the combination with a traveling bulb holder for holding a bulb with the neck down, burners mounted adjacent the path of said holder to heat a narrow zone on the neck and sever the waste end of the neck, a radially movable flaring tool for expanding the bore of the neck and flaring its edge, and an abutment for sustaining theneck in position against the radial thrust of the flaring tool. c

22. In a machine of the character described, the combination with a traveling bulb holder for holding a bulb with the neck down, burners mounted adjacent the path of said holder to heat a narrow zone on the neck and sever the'waste end of the neck, a radially movable flaring tool for expanding the bore of the neck and flaring its edge,

and a wheel mounted in position to bring its rim against the neck of the bulb in the line of thrust exerted by said tool duringr Certifczite of Correction.

Itis hereby certified that in Letters Patent No. 1,404,268, granted January 24, 1922, upon the application of William R. Burrows, of N owark, New Jersey, for an improvement in Methods of and Apparatus for Finishing Bulbs, errors appear in the printed specification requiring correction as follows: Page 5, line 2, claim 2, for the word niolt" road mold; page (i, line 30, claim 1X, after the Word "und insert the Word comino/1L; and that the said Letters Patent should be read with these corrections therein that the saine may conform to the record of the case in the Patent Olire.

Signed and sealed this ltii day of April, A. D.. 1922.

[SEALJ KARL FENNING,

Acting Commissioner of Patents. 

